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| author | Mike Kravetz | 2017-02-23 00:42:49 +0100 |
|---|---|---|
| committer | Linus Torvalds | 2017-02-23 01:41:28 +0100 |
| commit | fa4d75c1de13299c61b5e18a1ae46bc00888b599 (patch) | |
| tree | 73ca3cf8aac2fa991fc7310658145d49772f0b49 | |
| parent | userfaultfd: non-cooperative: wake userfaults after UFFDIO_UNREGISTER (diff) | |
| download | kernel-qcow2-linux-fa4d75c1de13299c61b5e18a1ae46bc00888b599.tar.gz kernel-qcow2-linux-fa4d75c1de13299c61b5e18a1ae46bc00888b599.tar.xz kernel-qcow2-linux-fa4d75c1de13299c61b5e18a1ae46bc00888b599.zip | |
userfaultfd: hugetlbfs: add copy_huge_page_from_user for hugetlb userfaultfd support
userfaultfd UFFDIO_COPY allows user level code to copy data to a page at
fault time. The data is copied from user space to a newly allocated
huge page. The new routine copy_huge_page_from_user performs this copy.
Link: http://lkml.kernel.org/r/20161216144821.5183-17-aarcange@redhat.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/mm.h | 3 | ||||
| -rw-r--r-- | mm/memory.c | 25 |
2 files changed, 28 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 3787f047a098..6bc7f2c1a6d1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2424,6 +2424,9 @@ extern void clear_huge_page(struct page *page, extern void copy_user_huge_page(struct page *dst, struct page *src, unsigned long addr, struct vm_area_struct *vma, unsigned int pages_per_huge_page); +extern long copy_huge_page_from_user(struct page *dst_page, + const void __user *usr_src, + unsigned int pages_per_huge_page); #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ extern struct page_ext_operations debug_guardpage_ops; diff --git a/mm/memory.c b/mm/memory.c index ececdc4a2892..4ade940d105c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4152,6 +4152,31 @@ void copy_user_huge_page(struct page *dst, struct page *src, copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); } } + +long copy_huge_page_from_user(struct page *dst_page, + const void __user *usr_src, + unsigned int pages_per_huge_page) +{ + void *src = (void *)usr_src; + void *page_kaddr; + unsigned long i, rc = 0; + unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; + + for (i = 0; i < pages_per_huge_page; i++) { + page_kaddr = kmap_atomic(dst_page + i); + rc = copy_from_user(page_kaddr, + (const void __user *)(src + i * PAGE_SIZE), + PAGE_SIZE); + kunmap_atomic(page_kaddr); + + ret_val -= (PAGE_SIZE - rc); + if (rc) + break; + + cond_resched(); + } + return ret_val; +} #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS |